Micro-Electro-Mechanical Systems (MEMS) typically integrate electronic and mechanical elements, sensors, actuators, and the like on a silicon substrate utilizing micro-fabrication technology. The fabrication and integration of these elements on a single substrate makes possible the realization of complete systems on a chip. However, MEMS radio frequency and optical relays commonly use electrostatic actuators requiring 80 to 120 volts DC for operation. Consequently, exploitation of the MEMS technologies has generally been limited by the availability of inexpensive, compact sources of energy.
In larger consumer electronic devices, such as notebook computers and cameras, batteries are typically formed by connecting multiple individually packaged cells in series in order to create batteries with more power and higher voltages. Another approach to creating a high voltage battery is to form cathode and anode electrode layers on opposite sides of an impervious conductive foil and then stack the bipolar sheets with intervening ionically conductive electrolyte separators one upon the other. The resulting so called bipolar battery effectively connects each pair of electrodes in series thereby forming a high voltage without requiring a significantly larger amount of space. Such bipolar batteries are difficult to manufacture and are generally not in prevalent use. Moreover, current battery-on-semiconductor technologies generally do not permit the formation of such multi-layer bipolar batteries. For example in the case of lithium thin film batteries in MEMS, anode materials generally cannot be subjected to the anneal temperatures required for cathode materials. Accordingly, the fabrication of anode and cathode on a common conductive substrate is not feasible and such battery structures are generally limited to a single battery cell layer produced by sequentially fabricating the cathode, the ionically conductive electrolyte separator and then the anode individually. As a result, a significant area of a MEMS substrate must be set aside to form a large number of single layer batteries to provide sufficiently high voltages for the device. This limits the minimum size possible for some types of integrated batteries. Accordingly, the minimum size possible for MEMS devices including such batteries is also effectively limited.